{
  "type": "FeatureCollection",
  "features": [
    {
      "$source": "gsml:MappedFeature"
    },
    {
      "@id": "${@id}",
      "@type": [
        "Feature",
        "gsml:MappedFeature",
        "http://vocabulary.odm2.org/samplingfeaturetype/mappedFeature"
      ],
      "name": "${gml:name}",
      "gsml:positionalAccuracy": {
        "type": "gsml:CGI_NumericValue",
        "value": "${gsml:positionalAccuracy/gsml:CGI_NumericValue/gsml:principalValue}"
      },
      "gsml:GeologicUnit": {
        "$source": "gsml:specification/gsml:GeologicUnit",
        "$filter": "xpath('gml:description') = 'Olivine basalt'",
        "@id": "${@id}",
        "description": "$filter{xpath('gml:description')='Olivine basalt'},${gml:description}",
        "gsml:geologicUnitType": "urn:ogc:def:nil:OGC::unknown",
        "gsml:composition": [
          {
            "$source": "gsml:composition"
          },
          {
            "gsml:compositionPart": [
              {
                "$source": "gsml:CompositionPart"
              },
              {
                "gsml:role": {
                  "value": "${gsml:role}",
                  "@codeSpace": "$filter{xpath('../../gml:description')='Olivine basalt'},urn:cgi:classifierScheme:Example:CompositionPartRole"                },
                "proportion": {
                  "$source": "gsml:proportion",
                  "@dataType": "CGI_ValueProperty",
                  "CGI_TermValue": {
                    "@dataType": "CGI_TermValue",
                    "value": {
                      "value": "${gsml:CGI_TermValue}",
                      "@codeSpace": "some:uri"
                    }
                  }
                },
                "lithology": [
                  {
                    "$source": "gsml:lithology",
                    "$filter": "xpath('gsml:ControlledConcept/@id') = 'cc.2'"
                  },
                  {
                    "@id": "${gsml:ControlledConcept/@id}",
                    "name": {
                      "value": "${gsml:ControlledConcept/gsml:name}",
                      "@lang": "en"
                    },
                    "vocabulary": {
                      "@href": "urn:ogc:def:nil:OGC::missing"
                    }
                  }
                ]
              }
            ]
          }
        ]
      },
      "geometry": "${gsml:shape}"
    }
  ]
}
